Just how many people are at Bonnaroo this year? That question has been hard to get a handle on -- especially because no single performer in the festival's first three days appeared to really bring out all of the attendees en masse.

By the end of Sunday night, we had our answer. A ton of people are at Bonnaroo. Tens and tens of thousands. And almost all of them, it seems, stuck around to see Elton John close out this year's fest.

"This is my first ever festival in America," he told his young audience, unbelievably. "And I heard it's the best one."

It all opened with the 11-minute, semi-instrumental epic, "Funeral for a Friend/Love Lies Bleeding." John later explained that he was starting the show with the entire first side of landmark album, "Goodbye Yellow Brick Road," which celebrated its 40th anniversary last year. That meant that songs No. 2 and 3 were "Candle in the Wind" and "Bennie and the Jets," and throughout the night, John doled out the hits early and often, while also indulging in deeper cuts that worked in the wide open space.Bonnaroo was obviously a special occasion for the British rock legend. His set list seemed miles removed from the shows he dutifully plays for baby boomers across the county, or during residencies in Las Vegas. Sunday night's concert was for college kids who couldn't pay top dollar to be front and center for him -- so instead, they sat in line all day in 90-degree weather.

A sea of smartphones started rolling video as John performed "Tiny Dancer" within the first 30 minutes, and soon the crowd was letting illuminated balloons loose in the night sky as "Rocketman" played out. After that display, he had to get up from his piano stool and humorously bow down to his audience.

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Elton John closes out the 13th Bonnaroo Music & Arts Festival on Sunday, June 15, in Manchester, Tenn.(Photo: John Partipilo / The Tennessean)

There were several other one-night-only moments. John dedicated "Don't Let the Sun Go Down On Me" to the late Casey Kasem, who died Sunday morning, and brought out a surprise special guest -- Nashville piano pop star Ben Folds -- to sing and play on "Grey Seal," another cut from "Goodbye."

John told them that the feedback he and his band got from their audiences was what made them continue to perform, and the Bonnaroo crowd gave them plenty of reason to keep going on Sunday.

When the cheers refused to die down when he left the stage, John returned to treat fans to the song that started his career -- "Your Song" -- and "Crocodile Rock," and assured them that it had been an exceptional evening.